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Cycling matter in chemical reactions
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`` You should have realized by now that matter is not lost in a chemical reaction. All the atoms or ions in the reactants are present in the products.
`` In the investigation below you will investigate the movement of copper ions through a series of reactions.
INVESTIGATION 3.4: The cycling of copper ions through a series ``of reactions
See appendix for equipment list.
Copper carbonate can irritate the skin and ingestion and inhalation of dust is harmful. H2SO4 is corrosive. Wear eyewear and gloves.
1. Weigh precisely about 2 g of copper II carbonate (CuCO3) on to a piece of filter paper. Record the mass here:
Buchner funnel
PR E V ON IE LY W
2. What color is the copper carbonate?
3. Weigh a clean and dry test tube and record the mass:
4. Carefully place all the copper II carbonate into the test tube (don't leave any behind!). Attach the test tube to a clamp stand. Place a rubber cork and delivery tube on the end of the test tube and place the delivery tube in a beaker of limewater. 5. Place a Bunsen burner under the test tube and carefully heat the copper carbonate. Observe the change in the limewater. What gas is being produced?
6. Note the color change in the copper carbonate as it is heated. What color does the copper carbonate turn? What is this new powder?
7. When the color change is complete (the powder is all the same color) turn off the Bunsen and let the test tube and powder cool. 8. Reweigh the test tube and powder. Calculate the mass of the powder:
9. Weigh and record the mass of a clean, dry 100 mL beaker and place all the powder from the test tube into the beaker. Reweigh the beaker and powder and record the mass: 10. Add 80 mL of 1 mol/L H2SO4 to the beaker. Stir the solution with a clean glass stirring rod. Record the color change in the solution. What is this new solution? 11. Use steel wool or sandpaper to clean any coating from a large iron nail. Record the mass of the nail:
12. Add the cleaned nail to the solution and leave the solution overnight.
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13. Record the color change of the solution and any other observations of the reaction:
15. Record the mass of the powder. What is this new powder?
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14. Filter the solution to recover the new powder that has formed on the iron nail. Rinse the filtered powder with distilled water. The powder will need to be dried. Place the powder and filter paper onto a Buchner funnel to remove any remaining distilled water. If you have a drying oven, place the powder and filter paper into the oven just long enough to dry the powder completely.